Evolution of the cosmic matter density field with a primordial magnetic field
Evolution of the cosmic matter density field with a primordial magnetic field
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宇宙物质密度场与原始磁场的演化
DOI：
10.1103/physrevd.93.043004
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发表时间：
2016
影响因子：
5
通讯作者：
Dai. G. Yamazaki
中科院分区：
文献类型：
--
作者：
Dai. G. Yamazaki
宇宙磁场影响宇宙物质密度场的时间演化。宇宙流体的阿尔文速度平方与原初磁场（PMF）的系综平均能量密度成正比，它可以防止物质密度场在视界尺度上崩溃。 PMF 系综平均能量密度的存在也延迟了物质-辐射相等时间。 PMF 的系综平均能量密度还通过 Meszaros 效应和势衰变影响物质功率谱 (MPS)。由于PMF的系综平均能量密度不是一阶扰动，而是宇宙学线性扰动方程中的零阶源，为了正确理解PMF对MPS的整体影响，我们应该在线性摄动理论中同时考虑PMF的零阶源和一阶源的影响，对以前用PMF研究MPS的方法进行重大修改。我们首次将 PMF 零阶源的影响应用于 MPS 的理论计算。我们还分析了 PMF 对 MPS 的总体影响。 CMB 偏振受到弱透镜效应的影响。弱透镜效应由 MPS 决定。因此，我们必须考虑PMF的零阶源，才能正确理解MPS和CMB偏振。
A cosmological magnetic field affects the time evolution of the cosmic matter density field. The squared Alfven velocity of the cosmic fluid is proportional to an ensemble average energy density of a primordial magnetic field (PMF), and it prevents the matter density field from collapsing in the horizon scale. The matter-radiation equality time also is delayed by the presence of the ensemble average energy density of the PMF. The ensemble average energy density of the PMF also affects the matter power spectrum (MPS) through the Meszaros effect and the potential decay. Since the ensemble average energy density of the PMF is not a first order perturbation but a zero order source in the linear perturbation equations for the cosmology, to correctly understand the overall effect of the PMF on the MPS, we should significantly revise previous approaches to research for the MPS with the PMF by considering both the effects of the zero and first order sources from the PMF in the linear perturbation theory. We apply the effects of the zero order sources from the PMF to theoretical computations of the MPS for the first time. We also analyze the overall PMF effect on the MPS. The CMB polarization is affected by the weak lensing. The weak lensing is determined by the MPS. Therefore, we have to consider the zero order sources of the PMF to gain a correct understanding not only of the MPS but also the CMB polarization.